Distribution map of the Whooping Crane. blue: breeding, orange: wintering, green: year-round, grey: experimental year-round.
The Whooping Crane (Grus americana), the tallest North American bird, is an endangered crane species named for its whooping sound. Along with the Sandhill Crane, it is one of only two crane species found in North America. The Whooping Crane's lifespan is estimated to be 22 to 24 years in the wild. After being pushed to the brink of extinction by unregulated hunting and loss of habitat to just 21 wild and two captive Whooping Cranes by 1941, conservation efforts have led to a limited recovery. As of 2011, there are an estimated 437 birds in the wild and more than 165 in captivity.
An adult Whooping Crane is white with a red crown and a long, dark, pointed bill. Immature Whooping Cranes are cinnamon brown. While in flight, their long necks are kept straight and their long dark legs trail behind. Adult Whooping Cranes' black wing tips are visible during flight.
The species can stand up to 1.5 meters (5 ft) and have a wingspan of 2.3 meters (7.5 feet). Males weigh on average Template:Convert, while females weigh Template:Convert on average (Erickson, 1976). The body length averages about 132 cm (52 in). The standard linear measurements of the Whooping cranes are a wing chord length of Template:Convert, an exposed culmen length of Template:Convert and a tarsus of Template:Convert. The only other very large, long-legged white birds in North America are: the Great Egret, which is over a foot shorter and one-seventh the weight of this crane; the Great White Heron, which is a morph of the Great Blue Heron in Florida; and the Wood Stork. All three other birds are at least 30% smaller than the whooping crane. Herons and storks are also quite different in structure from the crane.
Their calls are loud and can carry several kilometers wide. They express "guard calls" for warning their partner about any potential danger, the crane pair will jointly call ("unison call") in a very rhythmic and impressive way in the early morning (after waking up), after courtship and for defending their territory. The first unison call every recorded in the wild was taken in the Whooping Cranes' wintering area in Aransas Wildlife refuge in December 1999 and is documented here
The muskeg of the taiga in Wood Buffalo National Park, Alberta, Canada, and the surrounding area was the last remnant of the former nesting habitat of the Whooping Crane Summer Range. However, with the recent Whooping Crane Eastern Partnership Reintroduction Project, Whooping Cranes nested naturally for the first time in 100 years in the Necedah National Wildlife Refuge in central Wisconsin, USA. They nest on the ground, usually on a raised area in a marsh. The female lays 1 or 2 eggs, usually in late-April to mid-May. The blotchy, olive-colored eggs average 2½ inches in breadth and 4 inches in length (60 by 100 mm), and weigh about 6.7 oz (190 g). The incubation period is 29–31 days. Both parents brood the young, although the female is more likely to directly tend to the young. Usually no more than one young bird survives in a season. The parents often feed the young for 6–8 months after birth and the terminus of the offspring-parent relationship occurs after about 1 year.
Breeding populations winter along the Gulf coast of Texas, USA, near Corpus Christi on the Aransas National Wildlife Refuge and along Sunset Lake in Portland, Matagorda Island, Isla San Jose, and portions of the Lamar Peninsula and Welder Point, which is on the east side of San Antonio Bay.
The Salt Plains National Wildlife Refuge in Oklahoma is a major migratory stopover for the crane population hosting over 75% of the species annually.
Six Whooping Crane wintered on Granger Lake in Central TX in 2011/2012. The group was made up of two mated pairs and their single offspring. One adult bird flew ahead to Aransas National Wildlife Refuge early in the season, but returned again to rejoin it's mate and offspring. Drought conditions in 2011 exposed much of the lake bed, creating ample feeding grounds for this small group of cranes.
The Whooping Crane is endangered mainly as a result of habitat loss, although whoopers are also still illegally shot despite this being subject to substantial financial penalties and possible prison time. At one time, the range for these birds extended throughout midwestern North America. In 1941, the wild population consisted of 21 birds. Conservation efforts have led to a population increase; as of April 2007 there were about 340 Whooping Cranes living in the wild, and another 145 living in captivity. The Whooping Crane is still one of the rarest birds in North America. The United States Fish and Wildlife Service confirmed that 266 Whooping Cranes made the migration to Aransas National Wildlife Refuge in 2007.
Among the many potential nest and brood predators include American Black Bear (Ursus americanus), Wolverine (Gulo gulo), Gray Wolf (Canis lupus), Red Fox (Vulpes vulpes), Lynx (Lynx canadensis), Bald Eagle (Haliaeetus leucocephalus), and Common Raven (Corvus corax). Golden eagles have killed young Whooping Cranes and fledgings. The bobcat has killed many Whooping Cranes in Florida and Texas; whether the birds were taken on their nests or not is not specified. In Florida, bobcats have caused the great majority of mortalities among Whooping Cranes, including several adults and the first chick documented to be born in the wild in 60 years. Patuxent Wildlife Research Center scientists believe that this is due to an overpopulation of bobcats caused by the absence or decrease in larger predators (the endangered Florida panther and the extirpated red wolf) that formerly preyed on bobcats. At least 12 bobcats have been trapped and relocated in an attempt to save the cranes. American alligators have taken a few Whooping Cranes in Florida.
These birds forage while walking in shallow water or in fields, sometimes probing with their bills. They are omnivorous and slightly more inclined to animal material than most other cranes. In their Texas wintering grounds, this species feeds on various crustaceans, mollusks, fish (such as eel), berries, small reptiles and aquatic plants. Potential foods of breeding birds in summer include frogs, small rodents, smaller birds, fish, aquatic insects, crayfish, clams, snails, aquatic tubers and, berries. Waste grain, including wheat, barley, and corn, is an important food for migrating Whooping Cranes.
Individual recognition, territorial and partnership fidelityEdit
While in earlier years, Whooping Crane chicks had been caught and banded (in the breeding areas of Wood Buffalo National Park), and it has delivered valuable insight into individual life history and behaviour of the cranes, this technique has been abanded due to imminent danger for the cranes and the people performing the catching and banding activities.
By recording guard and unison calls followed by frequency analysis of the recording, a "voiceprint" of the individual crane (and of pairs) can be generated and compared over time. This technique was developed by B. Wessling and applied in the wintering refuge in Aransas and also partially in the breeding grounds in Canada over 5 years. It delivered interesting results, i.e. that besides a certain fraction of stable pairs with strong affinity to their territories, there is a big fraction of cranes who change partners and territories. Only one of the exciting results was to identify the "Lobstick" male when he still had his band; he later lost his band and was recognized by frequency analysis of his voice and then was confirmed to be over 26 years old, and still productive.
The Whooping Crane was declared endangered in 1967. Although believed to be naturally rare, the crane has suffered major population deprivations due to habitat destruction and over-hunting. The population has gone to an estimated 10,000+ birds before the settling of Europeans on the continent to 1,300-1,400 birds by 1870 to 15 adults by 1938. The current population is approximately 382.
During the past two years, five Whooping Cranes in the Eastern population, which numbers about 100 in total, have been illegally shot and killed. One of the dead cranes was the female ("First Mom") who was the first captive raised and released whooper to successfully raise, along with her mate, a chick to adulthood in the wild in the East, in 2006. This was a particular blow to that population because whoopers in the East do not yet have an established successful breeding situation. Various agencies and individuals have offered rewards for the apprehension of the persons responsible.
Although the individuals responsible for the deaths of four of the cranes have not yet been apprehended, on March 30, 2011, Wade Bennett, 18, of Cayuga, Indiana and an unnamed juvenile pled guilty to killing First Mom. After killing the crane, the juvenile had posed holding up its body. Bennett and the juvenile were sentenced to a $1 fine, probation, and court fees of about $500, a penalty which was denounced by various conservation organizations as being too light. The prosecuting attorney has estimated that the cost of raising and introducing to the wild one Whooping Crane could be as much as $100,000.
In October 2011, two juveniles were apprehended for shooting to death two of the first ten Whooping Cranes in an experimental Jefferson Davis parish, Louisiana, non-migratory population.
On the other hand, attempts have been made to establish other breeding populations in captivity.
- One project by the United States Fish and Wildlife Service and the Canadian Wildlife Service was initiated in 1975 involved cross-fostering with Sandhill Cranes to establish a second self-sustaining flock. Although 85 chicks from the 289 Whooping Crane eggs transplanted into Sandhill Crane nests learned to migrate, the Whooping Cranes failed to mate with other Whooping Cranes due to imprinting on their Sandhill foster parents; the project was discontinued in 1989. No members of this population survive. This effort and the problem of imprinting is explored in the 1976 documentary A Great White Bird.
- A second involved the establishment of a non-migratory population near Kissimmee, Florida by a cooperative effort led by the U.S. and Canadian Whooping Crane Recovery Team in 1993. As of December 18, 2006, this population numbered about 53 birds, but a decision was made not to introduce further birds into this population until problems with high mortality and lack of reproduction are resolved, and as of May 2011, the population had shrunk to 20 cranes.
- A third attempt has involved reintroducing the Whooping Crane to a new flyway established east of the Mississippi river. This project uses isolation rearing of young Whooping Cranes and trains them to follow ultralight aircraft, a method of re-establishing migration routes pioneered by Bill Lishman and Joe Duff when they led Canada Geese in migration from Ontario, Canada, to Virginia and South Carolina in 1993. The non-profit organization which is responsible for the ultralight migrations is Operation Migration, and the larger group, WCEP (the Whooping Crane Eastern Partnership), oversees all aspects of the Eastern Introduced Flock. They are now also releasing fledged cranes directly into the established population, to learn the migratory behavior from their peers (Direct Autumn Release). One Whooping Crane from the Eastern Migratory Population (EMP) has been the recipient of special attention from conservationists for several years. This crane was given the name "Number 16-05" because he was the sixteenth Whooping Crane to be tracked and tagged in 2005. That year, #16-05 collided with an ultralight plane, and because of an injury resulting from this collision, he missed the autumn portion of that year's northern migration. He also had difficulty flying during his juvenile winter, however, he exhibited no flying impairment during the spring migration.
- Subsequent to hatching, the Operation Migration cranes are taught to follow their ultralight aircraft, fledged over their future breeding territory in Wisconsin, and led by ultralight on their first migration from Wisconsin to Florida; the birds learn the migratory route and then return, on their own, the following spring. This reintroduction began in fall 2001 and has added birds to the population in each subsequent year (Except that in early 2007, a disastrous storm killed all of the 2006 yearlings after their arrival in Florida.).
- As of May, 2011, there were 105 surviving Whooping Cranes in the Eastern Migratory Population (EMP), including seventeen that had formed pairs, several of which are nesting and are incubating eggs. Two Whooping Crane chicks were hatched from one nest, on June 22, 2006. Their parents are both birds that were hatched and led by ultralight on their first migration in 2002. The chicks are the first Whooping Cranes hatched in the wild, of migrating parents, east of the Mississippi, in over 100 years. One of these young chicks was unfortunately predated on the Necedah National Wildlife Refuge. The other young chick, a female, has successfully migrated with her parents to Florida. As noted above, in early February, 2007, 17 yearlings in a group of 18 were killed by the 2007 Central Florida tornadoes. All birds in that flock were believed to have died in the storms, but then a signal from one of the transmitters, "Number 15-06", indicated that it had survived. The bird was subsequently relocated in the company of some Sandhill Cranes. It died in late April from an as yet unknown cause, possibly related to the storm trauma. Two of the 4 DAR Whooper chicks from 2006 were also lost due to predation. However, as of December, 2010, 105 birds had become established in the eastern United States population.
- Due to the vulnerability of the Florida non-migratory population, an attempt is being made to establish a second non-migratory population in Louisiana's White Lake Wetlands Conservation Area. In March 2011, 10 cranes were released, but all but three had been lost by the time a second group of 16 were released in December. This is a cooperative effort of the US Fish and Wildlife Service, the US Geological Survey, the Louisiana Department of Wildlife and Fisheries, the Louisiana Cooperative Fish and Wildlife Research Unit at LSU, and the International Crane Foundation.
In Wood Buffalo National Park, the Canadian Wildlife Service counted 73 mating pairs in 2007. They produced 80 chicks, of which 40 survived to the fall migration, and 39 completed the migration to Aransas National Wildlife Refuge. In May 2011, there were 78 mating pairs and 279 total birds.
|This page uses Creative Commons Licensed content from Wikipedia (view authors).|
- BirdLife Species Factsheet.
- ARKive - images and movies of the Whooping Crane (Grus americana)
- International Crane Foundation's Whooping Crane page Breeds Whooping Cranes for reintroduction projects and is a research center for all of the world's cranes.
- Patuxent Wildlife Research Center The largest captive breeding population is housed here. They breed and train the young for release into the wild
- Whooping Crane Eastern Partnership This group overseeing the EMP reintroduction efforts
- Operation Migration This group trains and leads the cranes from Wisconsin to Florida using ultralight aircraft
- Louisiana Department of Wildlife and Fisheries site dealing with the experimental Louisiana population
- Journey North A website for teachers and children that follows the migrations of many species including the Whooping Crane
- Environment Canada Western Migatory Population, Whooping Crane Information
- Crane World The use of artificial vocal communication in training the Whoopers to follow the aircraft; see especially Summary of sonographical work for Whooping Cranes Savings Program
- The Nature Conservancy works to protect habitat for the Whooping Crane
- World Wildlife Fund Works to protect the Whooping Crane and all endangered species.
- Three White Cranes, Two Flyways, One World An educational website that links schools along the eastern Whooping Crane flyway in the USA with schools along the eastern flyways of the Siberian and Red-crowned Cranes in Russia and China.
- Photos of the Whooping Crane by renowned nature photographer Klaus Nigge